Device for filtering ambient air

Abstract

The invention relates to a device (100) for filtering ambient air, comprising: a reactor (110) designed to electrochemically react a reactant with an oxidising agent, wherein at least one fluid (230) can be generated as a product via the electrochemical reaction; a filter system (200) with a first fluid reservoir (220); wherein a first line connection (170) is formed between the reactor (110) and the first fluid reservoir (220), via which the generated fluid (230) can flow from the reactor (110) to the first fluid reservoir (220); wherein the filter system (200) is designed to bring ambient air into contact with the generated fluid (230) in the fluid reservoir (220), so that impurities can be filtered out of the ambient air; wherein a second connecting line (150) is formed between the filter system (200) and the reactor (110), via which the filtered ambient air of the filter system (200) can be supplied to the reactor (110) as an oxidising agent for the electrochemical reaction.

Description

[0001] DEVICE FOR FILTERING AMBIENT AIR

[0002] The present invention relates to a device for filtering ambient air, an electrically driven system, and a method for filtering ambient air.

[0003] Energy conversion systems are known in which electrical energy can be generated through an electrochemical reaction using an oxidizing agent and a fuel. These systems include fuel cell systems.

[0004] A fuel cell system can be used, for example, to generate electrical energy to operate an electric motor for an electrically powered vehicle. The fuel cell system can comprise a fuel cell stack with a plurality of fuel cells arranged side by side. In a fuel cell, an electrolyte layer, in particular a proton-conducting polymer electrolyte membrane, is arranged between two electrodes, a cathode and an anode. Electrical energy can be generated in the fuel cell by reacting a fuel with an oxidizing agent, in particular oxygen.

[0005] To provide the oxidant, ambient air can first be fed to the fuel cell. In addition to the desired oxidant, the ambient air contains contaminants or pollutants. These contaminants can include ammonia, nitrogen oxides, ozone, sulfur oxides, carbon monoxide, hydrogen sulfide, and others. In addition, the ambient air may also contain dust and salts such as sodium chloride.

[0006] These contaminants can adversely affect the electrochemical reaction in the fuel cell and thus the operation of the fuel cell, and can also lead to damage to the fuel cell.

[0007] It is therefore important that the fuel cell system has a filter system designed to filter out harmful contaminants from the ambient air before it is used for the electrochemical reaction in the fuel cell.

[0008] Air filters, particularly paper filters or activated carbon filters, can be used to remove particulate pollutants and other contaminants from the contaminated ambient air. These air filters must be cleaned or replaced regularly. This creates additional effort and costs. Furthermore, additional materials may be required when replacing the air filters.

[0009] The present invention is based on the object of providing a device for filtering ambient air which enables improved sustainable operation.

[0010] This object is achieved according to the teaching of the independent claims. Various embodiments and further developments of the invention are the subject of the dependent claims.

[0011] A first aspect of the solution relates to a device for filtering ambient air, comprising: (i) a reactor, in particular a fuel cell, which is configured to electrochemically react a reactant, in particular a fuel, with an oxidizing agent, in particular oxygen, wherein at least one liquid, in particular water, can be generated as a product by the electrochemical reaction; (ii) a filter system with a first liquid reservoir; (iii) wherein a first connecting line is formed between the reactor and the first liquid reservoir, whereby the generated liquid can flow from the reactor to the first liquid reservoir; (iv) wherein the filter system is configured to bring ambient air into contact with the generated liquid in the liquid reservoir, so that impurities, in particular solid or liquid particles, in particular salts, can be filtered out of the ambient air;(v) wherein a second connecting line is formed between the filter system and the reactor, whereby the filtered ambient air of the filter system can be supplied to the reactor as an oxidant for the electrochemical reaction. The terms "comprises," "includes," "includes," "has," "has," "with," or any other variation thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a process or apparatus comprising or having a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or that are inherent in such a process or apparatus.

[0012] Furthermore, unless explicitly stated to the contrary, "or" refers to an inclusive "or" rather than an exclusive "or." For example, a condition A or B is satisfied by one of the following conditions: A is true (or present) and B is false (or absent), A is false (or absent) and B is true (or present), and both A and B are true (or present).

[0013] The terms "a" or "an" as used herein are defined as "one or more." The terms "another" and "another," and any other variations thereof, are defined as "at least one other."

[0014] The term "plurality" as used here is to be understood as meaning "two or more".

[0015] The term “configured” or “set up” to fulfil a specific function (and respective variations thereof) as used here means that the corresponding device is already in a design or setting in which it can carry out the function or is at least adjustable – i.e. configurable – so that it can carry out the function after being set accordingly. The configuration can be carried out, for example, by appropriately setting parameters of a process sequence or of switches or the like for activating or deactivating functionalities or settings. In particular, the device can have a plurality of predetermined configurations or operating modes, so that the configuration can be carried out by selecting one of these configurations or operating modes.The term "fuel cell" as used here refers in particular to a device in which chemical energy is converted directly into electrical energy through an electrochemical reaction of a fuel with an oxidizing agent. For this purpose, an electrolyte layer can be provided in the fuel cell between two layers designed as electrodes. The electrolyte layer is designed, for example, as a polymer electrolyte membrane (PEM), which must be moist during operation in order to be able to conduct protons. A fuel, for example hydrogen, is dissociated at an electrode provided as the anode. The protons produced can diffuse through the membrane to the electrode used as the cathode, where they react with an oxygen atom of the oxidizing agent reduced by the cathode, forming water (formally: 2 H). + + O 2 - H2O).

[0016] The device according to the first aspect makes it possible to filter the ambient air through liquid, in particular water, generated by the reactor before ambient air is supplied to the reactor for the electrochemical reaction. The water is generated by the electrochemical reaction or the water is a product of the electrochemical reaction. Therefore, no separate air filter, which would have to be replaced regularly, is required to filter the ambient air. In this respect, potential maintenance effort and material costs can be reduced. Likewise, with the present device, it is not necessary to provide liquid for filtration from an external liquid source. Instead, the liquid generated by the device itself can be used. This further reduces the effort required to operate the filtration.The device can therefore be operated sustainably and with comparatively little effort. In this respect, the present device can be described as a self-renewing device with regard to the use of liquid generated by the device for filtering the ambient air.

[0017] Preferred embodiments of the device are described below, which can each be combined with one another and with the other aspects described as desired, unless this is expressly excluded or technically impossible. In some embodiments, the filter system has a gas separation device, in particular a centrifugal separator, which is designed to separate liquid or solid particles contained in the ambient air from the ambient air depending on a physical property of the particles, in particular their mass, before filtering through the liquid, and to bring them into contact with the liquid. This allows the ambient air to be filtered more effectively, since the particles are fed into the liquid depending on the physical property, whereas gas molecules that are lighter than the particles are not fed into the liquid.

[0018] In some embodiments, the filter system comprises a humidification device, in particular a spray device, which is configured to humidify the ambient air flowing into the filter system. This allows, in particular, water-soluble substances, such as salts, which may be present in the ambient air, to be bound and more effectively introduced into the liquid, thus filtering them out of the ambient air.

[0019] In some embodiments, the filter system has a heating device for heating the first liquid reservoir. This allows the liquid in the liquid reservoir to be heated, and in particular, freezing of the liquid at outside temperatures below freezing can be prevented. Freezing of the liquid would result in the ambient air no longer being able to be filtered, or at least only to a greatly reduced extent, and thus largely unfiltered ambient air would be supplied to the reactor. Furthermore, the heating device can achieve a liquid temperature that is preferred for the operation of the device. Likewise, after a prolonged shutdown of the reactor during which the liquid was frozen, the heating device can enable the liquid to thaw, in particular before the reactor is started up.

[0020] In some embodiments, the device comprises an electrically controlled pump for conveying a predetermined volume of the generated liquid from the reactor to the liquid reservoir. This ensures a predetermined volume of liquid in the liquid reservoir. This can be advantageous when the liquid reservoir is operated in a flow-through mode, i.e., the liquid is continuously supplied to the liquid reservoir by the pump and also continuously drained from the liquid reservoir.

[0021] In some embodiments, the first liquid reservoir has a closable opening through which liquid can be discharged from the first liquid reservoir. This allows liquid in which pollutants from the ambient air have been bound or dissolved to be discharged from the liquid reservoir, and the liquid reservoir can be refilled with liquid from the reactor. This allows for better filtering of pollutants from the environment.

[0022] In some embodiments, the closable opening has a continuously open state. This allows the liquid to be continuously drained, and liquid from the reactor can be continuously refilled into the liquid reservoir. This allows for even more effective filtration of the ambient air.

[0023] In some embodiments, the device has a second liquid reservoir for the generated liquid. This allows a portion of a volume of the liquid that can be generated by the reactor to be stored in the second liquid reservoir for an application other than filtering the ambient air. In particular, if the device is used in a motor vehicle, the generated liquid can be used for lubrication, for a windshield wiper system, or for extinguishing or cooling components. This allows the generated liquid to be put to an additional use, and a saving of a liquid that was intended in the vehicle for one or more of the aforementioned uses can be achieved.

[0024] In some embodiments, the device comprises: (i) a housing in which the reactor is arranged, wherein the housing is connected to the filter system by a third connecting line; (ii) a gas pump, in particular a gas jet pump, which is configured to suck gas out of the housing of the reactor and feed it to the filter system via the third connecting line. In particular, during operation of the reactor, gas in the housing can come into contact with dirt particles in the reactor. On the one hand, this gas is sucked out of the housing by the gas pump. On the other hand, this gas is filtered by the filter system and accordingly fed back to the reactor through the filter system. As a result, any gas present in the housing can be removed and used for the electrochemical reaction.

[0025] In some embodiments, the reactor comprises a fuel cell. During operation, the fuel cell generates water, in particular water. In particular, in the case of a truck, a volume of water in the order of magnitude of 70 l can be generated over a distance of the order of magnitude of 100 km. This volume can be sufficient for filtering the ambient air and for other applications. In the case of a fuel cell arranged in the housing, the tightness of the fuel cell can be reduced after a longer period of time, as a result of which small amounts of gas, in particular hydrogen, can escape from the fuel cell into the housing. By sucking this hydrogen away using the gas pump, it can be prevented that this hydrogen escapes into the environment.

[0026] A second aspect of the solution relates to an electrically driven system comprising a device according to the first aspect.

[0027] In some embodiments, the electrically powered system comprises a motor vehicle or an emergency power generator for a power system.

[0028] A third aspect of the solution relates to a method for filtering ambient air, comprising: (i) carrying out an electrochemical reaction with a reactant, in particular a fuel, and an oxidizing agent, in particular oxygen, through a reactor, wherein at least one liquid is generated as a product by the electrochemical reaction; (ii) feeding the generated liquid to a liquid reservoir of a filter system, wherein the ambient air is brought into contact with the generated liquid by the filter system, so that contaminants are filtered out of the ambient air; (iii) feeding the filtered ambient air to the reactor for an electrochemical reaction. The features and advantages explained with regard to the first aspect of the solution also apply accordingly to the further aspects described.

[0029] Further advantages, features and possible applications emerge from the following description of preferred embodiments in connection with the figure.

[0030] The figure schematically shows a fuel cell system 100 with a fuel cell 110 and a filter system 200 according to one embodiment.

[0031] The fuel cell 110 is arranged in a housing 120. The fuel cell 110 has an anode compartment 130 and a cathode compartment 140. An anode (not shown here) is arranged in the anode compartment 130, and a cathode (not shown here) is arranged in the cathode compartment 140. A proton-conducting membrane, in particular a polymer electrolyte membrane (not shown here), is arranged between the anode and the cathode. An oxidant is supplied to the cathode compartment through an oxidant line 150. A fuel is supplied to the anode compartment 130 through a fuel line 160. In the fuel cell 110, an electrochemical reaction takes place between the oxidant and the fuel, generating electrical energy and water as a reaction product. This water is fed through a water line 170 to a liquid reservoir 220 by means of a controlled pump (not shown here) of a filter system 200.The water pipe is made of a corrosion-resistant material, especially stainless steel.

[0032] The filter system 200 further comprises a filter housing 210 in which the liquid reservoir 220 is arranged. Ambient air is supplied through an opening in the filter housing 210 via an ambient air line 250. A corresponding air conveying device (not shown here) can be used for this purpose. The supplied ambient air is pre-filtered by a centrifugal separator 240, so that contaminants in the ambient air, in particular liquid or solid particles such as salt particles, which are heavier than the gas molecules of the ambient air, are supplied to the liquid reservoir 220 with the water. There, these contaminants are bound by the water or dissolve in the water. The corresponding gas flow can be directed not only to the water surface, but also through the water 230, whereby a particularly effective separation of the ambient air from remaining contaminants can be achieved.These impurities may include, in particular, ammonia or salts.

[0033] The gas molecules, which are lighter than the impurities, in particular oxygen, rise again and are fed to the cathode chamber 140 as an oxidizing agent through the oxidizing agent line 150.

[0034] The liquid reservoir 220 further has a closable opening 260 through which the water 230 can be drained. This can be advantageous if contaminants from the ambient air have already been filtered out by the water 230 over a longer period of time and thus bound by the water 230, thus saturating the water. Saturated water or filter water can be drained from the liquid reservoir 220 through the closable opening 260 and replaced with unsaturated water 230.

[0035] It is also possible for the water 230 to be continuously replaced, i.e. to flow continuously through the liquid reservoir 220.

[0036] Furthermore, the filter system 200 can have a spray device 270, through which the ambient air supplied to the filter system 200 can be sprayed with water droplets. The filter system 200 would therefore also be functional without the spray device 270. The water 230 required for this purpose is supplied to the spray device 280 via the water line 170. Substances that are water-soluble are bound by the water droplets and thus supplied to the liquid reservoir 220.

[0037] Furthermore, the filter system 200 has a heating device 280, which is arranged below the liquid reservoir 220 with respect to the plane of the drawing, in order to supply heat to the liquid reservoir 220 as needed. This is particularly advantageous at outside temperatures below the freezing point of the water 230 in order to prevent the water 230 from freezing. Likewise, the heating device 280 can enable the water 230 to thaw if, for example, a vehicle with the fuel cell system was parked for an extended period at temperatures below freezing, and the water 230 was frozen as a result. As a result, the heating device 280 can keep the water 230 in a liquid state or bring it into a liquid state, thereby ensuring that the ambient air is filtered by the filter system.

[0038] In the filter system 200, which can also be referred to as a liquid bath filter, supplied ambient air is filtered through the water 230 and fed to the fuel cell 110 for generating electrical energy through an electrochemical reaction. The water 230, in turn, is a product of this electrochemical reaction, so that the present fuel cell system 100 is self-renewing.

[0039] While at least one exemplary embodiment has been described above, it should be appreciated that a wide variety of variations exist. It should also be understood that the described exemplary embodiments are merely non-limiting examples and are not intended to limit the scope, applicability, or configuration of the devices and methods described herein. Rather, the foregoing description will provide one skilled in the art with guidance for implementing at least one exemplary embodiment, it being understood that various changes in the operation and arrangement of the elements described in an exemplary embodiment may be made without departing from the subject matter as defined in the appended claims, as well as their legal equivalents.

[0040] LIST OF REFERENCE SYMBOLS

[0041] 100 fuel cell system

[0042] 110 Fuel cell 120 Fuel cell housing

[0043] 130 Anode compartment

[0044] 140 Cathode compartment

[0045] 150 Oxidant line

[0046] 160 Fuel line 170 Water line

[0047] 200 filter system

[0048] 210 filter housing

[0049] 220 Liquid reservoir 230 Water

[0050] 240 centrifugal separators

[0051] 250 ambient air line

[0052] 260 Lockable opening

[0053] 270 Spraying device 280 Heating device

Claims

CLAIMS 1. Device (100) for filtering ambient air, comprising: A reactor (110) configured to electrochemically react a reactant with an oxidizing agent, wherein at least one liquid (230) can be generated as a product by the electrochemical reaction; a filter system (200) having a first liquid reservoir (220); wherein a first line connection (170) is formed between the reactor (110) and the first liquid reservoir (220), whereby the generated liquid (230) can flow from the reactor (110) to the first liquid reservoir (220); wherein the filter system (200) is configured to bring ambient air into contact with the generated liquid (230) in the liquid reservoir (220) so that impurities can be filtered out of the ambient air;wherein a second connecting line (150) is formed between the filter system (200) and the reactor (110), whereby the filtered ambient air of the filter system (200) can be supplied to the reactor (110) as an oxidizing agent for the electrochemical reaction; 2. Device (100) according to claim 1, wherein the filter system (200) comprises a gas separation device (240) which is configured to separate liquid or solid particles contained in the ambient air from the ambient air depending on a physical property of the particles before filtering by the liquid (230) and to bring them into contact with the liquid (230).

3. Device (100) according to claim 1 or 2, comprising a humidification device (270) which is configured to humidify ambient air flowing into the filter system (200).

4. Device (100) according to one of the preceding claims, comprising a heating device (280) for heating the first liquid reservoir (220).

5. Device (100) according to one of the preceding claims, comprising an electrically controlled pump for conveying a predetermined volume of the generated liquid (230) from the reactor (110) to the liquid reservoir (220).

6. Device (100) according to one of the preceding claims, wherein the first liquid reservoir (220) has a closable opening (260) through which liquid (230) can be discharged from the first liquid reservoir.

7. The device (100) of claim 6, wherein the closable opening (260) has a continuously open state.

8. Device (100) according to one of the preceding claims, comprising a second liquid reservoir for the generated liquid (230).

9. Device (100) according to one of the preceding claims, comprising: a housing (120) in which the reactor (110) is arranged, wherein the housing (120) is connected to the filter system (200) by a third connecting line; a gas pump configured to extract gas from the housing (120) of the reactor (110) and to supply it to the filter system (200) via the third connecting line.

10. Device (100) according to one of the preceding claims, wherein the reactor (110) comprises at least one fuel cell.

11. An electrically driven system comprising a device (100) according to any one of the preceding claims.

12. Electrically driven system according to claim 11, comprising a motor vehicle or an emergency power generator for a power supply system.

13. A method for filtering ambient air, comprising: Carrying out an electrochemical reaction with a reactant and an oxidizing agent through a reactor (110), wherein at least one liquid (230) is generated as a product by the electrochemical reaction; feeding the generated liquid (230) to a liquid reservoir (220) of a filter system (200), wherein the filter system (200) brings the ambient air into contact with the generated liquid (230) so that impurities are filtered out of the ambient air; Feeding the filtered ambient air to the reactor (110) for an electrochemical reaction.

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